Nowadays, conglomerate boards are manufactured in a continuous process by means of formers which pour a first layer of product of greater density and smaller size particles of the wood, mixed with glue and other active products, onto the band of a conveyor belt. A second layer is added to this layer, of greater thickness, lower density and smaller size particles, and finally another layer is added analogous to the first, poured on with another former, producing a sandwich arrangement. This mat of wood and glue particles can consist of a single size of particle, with a uniform composition, including of a known material such as DM.
Independently of the structure and composition of the mat that will be formed following the pressing of the board to the required thickness of the door, it initially has a thickness of the order of 90-170 mm which is poured onto the conveyor belt and, once pressed in the hot plate press, a thickness is obtained is of the order of 25-40 mm for standard doors.
It is then cut up by the manufacturer of the boards to the measurement provided by the door manufacturer, with the aim of easing the difficulty of movements and transportation owing to the large dimension of the boards obtained.
The door manufacturer cuts these boards and machines them in order to produce doors of the desired measurements, eliminating the portions corresponding to the voids which have to be paneled or glazed.
Invention patent P-200501869 claims a manufacturing system for conglomerate boards for doors, with the simultaneous formation of the voids for paneling or glazing, where the mat coming from one or three formers, depending on whether it has a constant density or consists of three layers of different densities with a sandwich type structure, is received on trays or moulds whose width preferably corresponds to the length of the doors to form and whose length is equivalent to a multiple of the width of the latter, with the particular feature that the bottom of the tray possesses apertures in correspondence with the soffits or voids which then have to be paneled or glazed, of equivalent dimensions.
The mould or tray includes some telescopic formwork in the contour of each aperture which provides a retractable characteristic so that the mat of wood and glue conglomerate particles can be received at an initial height prior to pressing, and which permits the difference in thicknesses to be absorbed as far as the thickness that it has to have after the compaction of the two hot plates of the gantry press in which the pressing or compaction is conventionally carried out.
The portions of mat or particles mixed with glue that filled those voids fall through the apertures, and are collected by a lower belt for being reused since they are sent directly to the corresponding hoppers for the formers.
In the installation and according to this invention patent that is cited, there exists an elevator feed device for the trays, which advances on a conveyor belt and continually passes below the formers which discharge the product onto these trays. They then advance towards the cold pre-pressing post where the thickness of the mat is reduced to approximately half and the air is expelled. By means of another elevator the trays are fed to the gap of the hot plate press and they are then collected by another elevator which leads them to the mould stripping post.
In a first Certificate of Addition to this main invention patent that is cited, the structure of the actual tray and its guide system in the pressing station were improved and simplified. The retractable formwork was materialized in the form of a simple triangular piece and the elastic deflector lamina, which used to exist in the main invention patent, perfectly absorbing the thicknesses of the mat of conglomerate particles and glue before and after the pressing.
In the second Certificate of Addition to this main invention patent that is cited, some improvements were contributed consisting of providing some supports in the front edge of the trays, these supports having an extension by way of a hook which is linked by a tooth provided in the hauling chains for the multiple charger and discharger of the press, in the different levels which the hot plates of that press have. Fitted to the rear support of the tray are also other supports with an emerging pad where the hook corresponding to the front part of the adjacent rear tray will link. The press is charged with new trays at the same time as the already pressed ones exit. There exists a charger for the trays which receives them one at a time from the pre-press and ascends as the trays are received until the charge is complete. Both the charger and the discharger include pairs of conveyor chains on which the trays rest for each level of the press and are supported on a bridge structure which slides on roller tracks with hydraulic action in order to produce the connection of the trays of the charger with those of the press and for connecting the discharger with those of the pre-press, respectively.